The problem of power consumption is an important factor that limits the development of mobile devices. With the development of the mobile Internet, more and more mobile devices are connected to the Internet through mobile networks, and power consumption generated by data transmission of the mobile networks is a large part in power consumption of the mobile devices. Therefore, reduction of power consumption generated by data transmission is of great significance to a solution for the problem of power consumption of the mobile devices.
States of a mobile network are divided into an idle channel, a Forward Access Channel (FACH) and a Dedicated Physical Data Channel (DCH) according to levels of power consumption. The mobile network is in an idle state in normal times when there is no data transmission, and there is little power consumption in the state. The change of network states during a single data transmission is described as follows: firstly, the network changes from the idle state to a DCH state in 2 seconds, and transmits user data at full speed in the DCH state (the DCH state is a high speed data transmission state and is also a state with the highest power consumption); the mobile network is maintained in the DCH state for 5 seconds after the data transmission is completed, and if there is no data that can be transmitted within these 5 seconds, immediately changes from the DCH state to an FACH state (the FACH state is a low speed data transmission state in which a transmission rate is relatively low and power consumption is also lower than that in the DCH state), remains in the FACH state for 12 seconds, and if there is still no data that can be transmitted during this period of time, immediately changes from the FACH state to the IDLE state. Thus, additional cost of power consumption of 2+5+12=19 seconds will be caused in a typical data transmission process. Wireless power consumption is wasted within this period of time without any data transmission. Besides, the states are maintained for different time values by different wireless network technologies and operators, but the additional cost on power consumption is generally inevitable. It can be found through analysis that for a given amount of data that needs to be transmitted, the power consumption generated by transmitting the data in multiple transmissions is higher than that generated by transmitting the data in one transmission, and the more the number of the transmissions, the higher the power consumption will be.
An existing smart phone system is a multitask system in which many applications run simultaneously, and data of a plurality of applications may be exchanged with the network concurrently. For example, a browser is used for surfing the internet in the foreground while QQ and WeChat are enabled to run in the background. The browser, QQ and WeChat will initiate their respective data transmission independently according to their own demands during any period of time. The total number of data transmission times in the mobile phone system is the sum of data transmission times of the browser, QQ and Wechat during this period of time (provided that the browser initiates data transmission for 3 times, QQ and WeChat initiate data transmission twice respectively, then the total number of data transmission times in the mobile phone system is 3+2+2=7 times). An ideal method is to centralize (combine) the 7 times of data transmission into one transmission, which can reduce the data transmission times in the mobile phone system, and reduce power consumption to the largest extent. However, this ideal method has two problems as follows:
1) some data transmission operations can be hardly centralized, such as page browsing; a data transmission operation has to be initiated each time when a user clicks a hyperlink, so as to obtain a new webpage to continue browsing; if this data transmission is postponed and combined with data transmission operations of other applications, it is apparent that demands of the user can be hardly met;
2) even if a data transmission operation can be postponed, it is still difficult to combine data transmission, it is necessary to know information indicating the time when other applications in the system will conduct data transmission, while the information can be hardly obtained.